1. Field of the Invention
The present invention relates to a smoking article and a wrapper for a smoking article that provide substantially reduced ignition propensity in the smoking article, particularly in a cigarette, and to an in line method of and apparatus for producing the wrapper and making smoking articles using the wrapper.
2. Description of the Prior Art
There is a recognition in the industry that the smoking article wrapper has a significant influence on the reduction of ignition propensity of the smoking article. Several solutions have been proposed to solve the problem of providing a low or reduced ignition propensity cigarette involving modification of the porosity of the smoking article wrapper.
For example, it is known that the burn characteristics of a wrapper can be modified by adding fillers, coatings or additives to the wrapper. U.S. Pat. No. 4,480,650 to Weinert discloses a self-extinguishing cigarette in which the interior surface of the wrapper is coated with clay. U.S. Pat. No. 4,889,145 to Adawns et al. discloses a cigarette wrapper having an area containing a discontinuous coating of porosity reducing composition. U.S. Pat. No. 4,615,345 to Durocher discloses a cigarette having cross-directional or circumferential bands treated with bum promoter wherein the untreated paper does not support combustion and the cigarette self-extinguishes when the cigarette burns into the untreated area of the wrapper. U.S. Pat. No. 4,453,553 to Cohn attempts to improve upon both sidestream smoke characteristics and fire resistance by the use of longitudinal stripes of burn rate reducing substances and optionally an additional layer of cigarette wrapper paper.
Modification of the smoking article wrapper by modifying the base paper properties in certain regions or applying to the base paper a cross-directional ring or band or a cross-directional strip of paper having different properties than the base paper have been proposed. For example, U.S. Pat. No. 4,945,932 to Mentzel et al. discloses a cigarette wrapper paper having annular zones of low permeability formed by a batonneing process. U.S. Pat. No. 4,739,775 to Hampl, Jr. discloses the application of circumferential bands of paper having reduced filler content onto the inside of the base paper to form smoking articles that are self-extinguishing in the two layer circumferentially banded zones. U.S. Pat. No. 5,474,095 to Allen et al discloses a wrapper paper having cross-directional or circumferential regions with increased basis weight that is produced in the papermaking process by depositing additional material onto the base web in the papermaking machine using a drum containing a plurality of slits.
The foregoing and other prior art attempts to reduce the ignition propensity of smoking articles, such as cigarettes, focus primarily upon creating zones of low permeability in the wrapper paper during the papermaking process and using the thus-formed paper slit to an appropriate width in the cigarette making process to form the outer wrapper for the cigarette. Insofar as is known, there has been no successful prior art process in which cross-directional zones of low or reduced permeability have been created on the cigarette wrapper paper in line, that is, during the cigarette making process.
In addition, the use of new chemical additives in a cigarette product to form low or reduced permeability zones of the cigarette wrapper paper to reduce the ignition propensity of the cigarettes is undesirable since such additives must undergo testing to insure that there are no adverse effects of adding the chemicals to the cigarettes.
It would be desirable to provide an in line process and apparatus for manufacturing a smoking article having reduced ignition propensity which does not require extensive equipment modifications or the use of new chemical additives that require extensive testing. It would also be desirable to provide a cigarette having reduced ignition propensity that can be made on slightly modified, conventional cigarette making machinery using readily available, conventional materials, including conventional wrapper papers and wrapper adhesives, without sacrificing the look, feel, taste and burn of a conventional cigarette or the speed and efficiency of the cigarette making machinery.